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Aug. 11, 2010 -- Potiga, a new epilepsy drug, should be approved in the U.S. as an add-on treatment, an FDA expert advisory panel today voted.

Potiga, known generically as ezogabine in the U.S. and as retigabine elsewhere, works differently than current epilepsy drugs. That's a good thing, as about a third of epilepsy patients do not get satisfactory seizure control from treatment

But Potiga can have dangerous side effects. Most worrying to the panel were the drug's effects on the bladder -- particularly urinary retention, sometimes resulting in urinary infections. But in the end, the panel agreed that this risk could be minimized by a patient-monitoring program.

Some panel members wanted the FDA to require a more stringent monitoring program than the one proposed by Valeant Pharmaceuticals International, which is developing the drug with GlaxoSmithKline. Other panel members wanted the FDA to ensure that doctors who prescribe Potiga would be vigilant for side effects and would use the drug only in patients for whom it is approved.

Panelists also expressed concern that doctors be alert for other side effects besides bladder problems in patients taking the drug. Based on clinical trials, those most commonly seen include drowsiness, dizziness, fatigue, and confusion.

Potiga is intended for the treatment of partial seizures, the most common type of seizure in adults. A partial seizure affects only part of the brain but may result in a wide range of symptoms.

The drug works by opening potassium signaling channels in the brain. This has the effect of stabilizing the electrical current in the brain and prevents the sudden bursts of activity that occur with seizures.

In an evaluation of Potiga clinical trials provided to the panel, the FDA said the drug helped cut the number of seizures patients experienced. Because it wears off quickly, the drug must be taken three times a day.